Polystichum lemmonii

{{Short description|Species of fern}}

{{speciesbox

| status = G4

| status_system = TNC

| image = Polystichum lemmonii (1).jpg

| genus = Polystichum

| species = lemmonii

| authority = Underw.

}}

Polystichum lemmonii is a species of fern known by the common names Lemmon's holly fern and Shasta fern. It is native to western North America from the Sierra Nevada of California north to Washington. It is also known from British Columbia, where there is an occurrence in the mountains above the Okanagan Valley.[http://www.env.gov.bc.ca/wld/documents/recovery/rcvrystrat/polystichum_lemmonii_rcvry_strat_010807.pdf Recovery strategy for the Lemmon's holly fern (Polystichum lemmonii) in British Columbia.] BC Ministry of Environment, July 2007. and another in the mountains near Harrison Lake. [https://www.inaturalist.org/observations/239335255]

Description

This fern produces several narrow, erect lance-shaped leaves 10 to 35 centimeters long. Each leaf (frond) is made up of many oval leaflets (pinnae) which are overlapping, folded, and twisted such that the leaves may appear almost cylindrical in outline. Leaflet margins are entire or bluntly dentate. Hitchcock, C.L. and Cronquist, A. 2018. Flora of the Pacific Northwest, 2nd Edition, p. 64. University of Washington Press, Seattle.Burke Herbarium Image Collection| http://biology.burke.washington.edu/herbarium/imagecollection/taxon.php?Taxon=Polystichum%20lemmonii

Habitat

P. lemmonii grows in mountainous habitat on ultramafic rock substrates, almost always in serpentine soils or among serpentine rocks. Though it grows in very restricted areas, P. lemmonii can be locally very abundant.

Gallery

Image:Polystichum lemmonii JHT IMG 7856.jpg|On ultramafic rock in Wenatchee Mountains

Image:Polystichum lemmonii JHT IMG 7857.jpg|Adaxial (upper) leaf surface

Image:Polystichum lemmonii JHT IMG 7860.jpg|Abaxial (lower) leaf surface with sori

Image:Polystichum lemmonii JHT IMG 5370.jpg|On Bean Peak in Wenatchee Mountains

References

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